Although a multitude of synthetic polymers has been made and is available commercially, both for domestic and industrial use, most of the commonly used synthetic polymers are very susceptible to the effects of light (particularly ultraviolet light) and heat. Exposure to light and heat, such as may be obtained simply from normal day-to-day use, will often seriously discolour or degrade the polymer, with the result that, at best, the polymer loses its aesthetic appeal and, at worst, the polymer may become completely useless. Accordingly, it is standard practice to incorporate into the majority of synthetic polymers one or more compounds, known as "polymer stabilizers", which have the effect of stabilizing the polymer against the effects of light and heat. Some classes of polyalkylated 4-aminopiperidine derivatives are disclosed in U.S. Pat. No. 3,684,765 and No. 3,904,581 and in German Offenlegungsschrift No. 2,621,870 and such compounds have been proposed for use as stabilizers for synthetic polymers. Moreover, German Offenlegungsschrift No. 2,611,208 discloses polymers whose side chains are linked to polyalkylated 4-aminopiperidine derivatives.
However, the known polyalkylated 4-aminopiperidine derivatives have a number of defects. For example, they are volatile or tend to colour the polymer in which they are incorporated and, as a result, they are not satisfactory for commercial use.